My dad signed everything when I was in k-12 as "Dad". I got called on it for signing in place on a permission slip (I wouldn't call it forging) in 2nd grade.

He had to come "bail me out" of the principals office, at which point he was irate saying "I signed it like that, I'll always sign it like that, that's my mark for school functions"

After looking up that consistent "marks" are legal substitutes for a signature, the principal finally backed down.

Small caps "Dad" with two underscores.

/CSB

It would be cool if your mark was L O N G Johnson. Probably would get some hits at diners and roadside cafes or such. in fact, if your mark can be dad with two underscores you might be able to swing this mark yourself. Let's see, Lawrence Oliver Nigel George Johnson. I was named after my English uncles.